Mail sorting apparatus



Nov. 30, 1965 E. A. KRUPQTICH 3,220,547

MAIL SORTING APPARATUS Filed Jan. 2, 1964 6 Sheets-Sheet l FIG. I

INVENTOR.

(Saw/4R0 A. Key/ o TICH ATTORNEYS E. A. KRUPOTICH MAIL SORTING APPARATUS Nov. 30, 1965 6 Sheets-Sheet 2 Filed Jan. 2, 1964 INVENTOR. fan A20 A. hfqupor/cfl ATTOR/VE V5 Filed Jan. 2, 1964 6 Sheets-Sheet 5 INVENTOR.

Nov. 30, 1965 E. A. KRUPOTICH 3,

MAIL SORTING APPARATUS Filed Jan. 2, 1964 6 Sheets-Sheet 4 INVENTOR.

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Nov. 30, 1965 E. A. KRUPOTICH MAIL SORTING APPARATUS 6 Sheets-Sheet 6 Filed Jan. 2, 1964 H. RCM m. N0 2 wk m M fwd Y B OE /m\ MN (Ill ATTOR/VE V5 United States Patent 3,220,547 MAIL SORTING APlARATUS Edward A. Krupotich, Hollywood, Calif., assignor to Econ-O-Post Corporation, San Francisco, Calif, a corporation of California Filed Jan. 2, 1964, Ser. No. 335,127 11 Claims. (Cl. 209-74) This invention relates to mail sorting apparatus and more particularly to mail sorting apparatus wherein envelopes containing mail are sorted according to weight.

In general it is an object of this invention to provide an improved mail sorting apparatus. Heretofore mail handling equipment has suffered from a number of shortcomings and has been of somewhat limited application.

It is an object of the present invention to provide improved mail handling apparatus wherein an accumulation of envelopes of differing randomly occurring thicknesses and weights are fed individually in a randomly occurring sequence to the sorting equipment.

It is another object of the invention to provide mail sorting apparatus wherein envelopes are intermittently advanced by conveyor means serving to discretely receive each envelope and advance same from one weighing platform to the next.

It is another object of the invention to provide mail handling apparatus of the foregoing kind wherein the conveying means is provided with means defining longitudinally spaced envelope engaging fiites extending laterally of the conveying means wherein the flites are pivotally supported to yield to forces contacting same which exceed a predetermined threshold of resilience and to otherwise provide unyielding contact with said envelopes.

It is a further object of the invention to provide mail handling apparatus including a series of weighing platforms wherein each platform is arranged to provide a weighing movement confined substantially to a vertical plane to accommodate disposition of an envelope positioned anywhere upon the weighing platform and including an ability to be tilted through a relatively large angle to divert envelopes therefrom having a weight exceeding a predetermined minimum.

These and other objects of the invention will become more readily apparent from the following description of a preferred embodiment when taken in conjunction with the drawing, in which:

FIGURE 1 is a plan view of a portion of the apparatus showing an envelope feeding station and conveyor means for advancing envelopes from one weighing platform to the next;

FIGURE 2 is an elevational section view taken along the line 22 of FIGURE 1;

FIGURE 3 is a simplified view in side elevation somewhat enlarged showing two of the weighing platforms and a portion of the belt drive arrangement;

FIGURE 4 is an enlarged simplified side elevation view showing a portion of means for sensing a jammed weighing platform whereby differential parallel bar movement serves to operate a control switch;

FIGURE 5 is a plan view of a portion of the apparatus showing the path of mail movement defined by the weighing platforms;

FIGURE 6 is a side elevational view partially broken Patented Nov. 30, 1965 away, for simplification of understanding, to show the parallelogram construction of a weighing platform;

FIGURE 7 is a simplified diagrammatic illustration showing operation of a weighing platform for diverting envelopes by tilting the platform;

FIGURE 8 is an enlarged simplified view showing means in the envelope feeding station serving to separate envelopes passing therethrough; and

FIGURE 9 is a timing and acceleration curve illustrating time sharing movements of various portions of the apparatus.

In general there is provided a mail sorting apparatus comprising means defining a mail depository zone adapted to accumulate a quantity of envelopes of differing randomly occurring thickness and weights. Intermittently moving conveyor means provided with envelope engag ing fiites operate over a path of mail movement through the apparatus. Feeding means serve to feed each of the envelopes individually from the depository zone in sequence to the conveyor means for movement along the path of mail movement.

Means are provided defining a plurality of cribs serving to receive envelopes diverted from said path. Each crib is disposed to receive those envelopes having a predetermined weight diflerent from that of envelopes received at the other cribs. A series of bistable weighing platforms define the mail movement path and are adapted to receive and weigh the envelopes. Each platform is arranged for vertical weighing movement from a raised to a lowered position upon receipt of an envelope of a predetermined minimum Weight associated with the particular platform. The predetermined minimum weight requisite becomes progressively less for the platforms at greater distances along the path measured from the depository zone. Means are provided to sense movement of each platform to its lowered position. Upon lowering any one or more platforms, means are provided to tilt them to divert the envelope disposed thereon into their associated receiving cribs.

Referring to the drawings, in which like elements are designated by like reference numerals throughout the various figures, there is shown means providing a mail depository zone adapted to accumulate a quantity of envelopes of differing randomly occurring thickness and weights. For example, as shown in the drawing there is provided a conveyor belt 10 trained about a pair of rollers 12, 14 and belt driven by a motor 16.

Belt 10 serves to feed the envelopes from an accumulation spread thereon, to enter them in sequence into the apparatus for sorting.

The motor 16 drives roller 12 to move belt 10 in envelope supplying direction to carry envelopes to an envelope separating station 18. Station 18 includes a belt driven feeder wheel 20 driven from a second motor 19 continuously in envelope delivering direction. Feeder wheel 20 carries a friction surface portion 22 extending around a limited arcuate extent of wheel 20 to provide intermittent frictional engagement with the bottom surfaces of envelopes being separated at station 18. Thus there is shown a rubber feed sector member trained about a pair of pins and adapted to extend upwardly above the surface of the path of mail movement. Feeder wheel 20 is mounted upon a shaft 24 which carries a cam 26 rotating therewith. A cam follower 28 rides the surface or" cam 26 to move a lever arm 30 forming one arm of a bell crank arrangement, the other arm of which is identified as 32. Briefly, the bell crank arrangement is formed between lever arm 30 and a pivot pin 34 disposed to carry a feed pressure yoke 36 provided with opposed adjusting screw 38 and spring 39 at the end thereof. Between the adjusting screw 38 and spring 39 is located the other leg 32 of the bell crank which operates as a feed pressure arm. The feed pressure arm, then, moves in accordance with the movement of cam follower 28. The free end of arm 32 carrries a feed pressure assembly 40 (FIGURE 8) including a boot shaped member 42, a pressure pad 44 fixed to the sole of boot 42 and a separator arm 46 supported on a pivot 48 through the toe of boot 42. A fixed friction wheel 50 is carried on the end of separator arm 46 for movement along a slot 52 forming the arch of boot 42. A spring 54 is interposed between pad 44 and separator arm 46 so as to urge the friction wheel 50 upwardly. A turnbuckle 56 is pivotally connected to separator arm 46 at its lower end and at its upper end carries a yoke 58 embracing a slide pin 60. A screw 61, loosely fitted in the arm 32, is threaded into pin 60. A spring 62 urges the pin 60 to the right as shown in FIGURE 8 to a position limited by the head of the screw 61 by acting against the end of arm 32. With such an arrangement it is seen that as the arm 32 is raised, the spring 54 raises the separator arm with respect to the pressure pad 44. The amount by which the arm 32 must be raised in order that the wheel 50 clears the pad 44 can be adjusted by the screw 61. For the position of elements shown in FIGURE 8, raising the feed pressure assembly 40 one quarter of an inch above the platform 63.

In order to move boot 42 in a substantially vertical plane a parallel arm 64 is disposed in substantially parallel relation to feed pressure arm 32 and is pivotally coupled to the upper end of boot 42 by a pin 66.

Operation of the envelope separating station 18 proceeds substantially as follows. Conveyor belt supplies envelopes preferably fanned out in an overlapping relationship to station 18. Arrival of an envelope 65 is sensed by a switch member 68 contacted by the envelope. Switch member 68, when contacted by the envelope, serves to de-energize motor 16 to discontinue feeding of envelopes by belt 10. The feed separator pressure assembly 40 is in its raised position under action of cam 26. Rotation of cam 26 by means of the shaft 24 and motor 19 serves to move boot 42 in a vertical direction downwardly against the envelope therebeneath. The movement of the envelope has, at this time, been arrested by operation of the switch 68 to discontinue movement of conveyor belt 10.

With these envelopes, whereby the boot 42 can be moved to within one quarter of an inch of the platform 63, the friction wheels 50 provide a drag on the top of the envelope 65 and on any envelopes which are stacked upon the envelope 65. The friction wheel 50 will contact the upper surface of an envelope therebeneath with a coefiicient of friction which is less than the coefficient of friction developed between friction surface 22 and the envelope. The friction between the wheel 50 and the paper is greater, however, than that between a paper to paper contact as found where a pair of envelopes are superimposed one upon the other. Accordingly, friction wheel 50 will serve to restrain advancing movement of a superimposed envelope while permitting the bottommost envelope to be transferred through station 18 when friction portion 22 has been rotated. Envelopes delivered from station 18 are received upon a continuously moving bridging conveyor 70, belt driven from a pulley 72.

In the case of thick envelopes, such as those more than one quarter of an inch thick, the possibility of superimposed envelopes is quite small. Moreover, with such thick envelopes, it is important that relatively little drag be presented to insure proper feeding by the lower rotating friction surface 22. For these reasons, the upper friction wheel 50 is held out of position when such thick envelopes hold the boot one quarter inch above the platform 63. In such instances, only the relatively smooth pressure pad 44 contacts the upper surface of the envelope and drag is maintained at a minimum.

The main conveyor means includes a cyclic carrier 74 trained about a pair of rollers 76 and a plurality of readily releasable projections 78 extending outwardly thereof. Projections 78 are disposed in columns and rows to define longitudinally spaced envelope engaging flites extending laterally of carrier 74. Each projection 78 is pivotally supported and resiliently loaded by means of a spring 80 to yield to forces contacting the projections 78 which exceed a predetermined threshold of resilience of spring 80. Spring 80 thereby provides an unyielding contact between projections 78 and envelopes engaged thereby whenever the forces acting upon projections 78 are below the threshold of resilience. Carrier 74 is intermittently driven by a Geneva mechanism including 21 Geneva gear 82 driven by motor 19.

As projections 78 move along the lower stretch of carrier 74 the distal ends of each projection 78 pass along slots 84 formed in weighing platforms 86. Each weighing platform 86 is supported on knife edge members 88 which serve to define an axis extending laterally of platforms 86.

Means are provided which serve to stabilize the platforms to confine the plane thereof substantially to the horizontal during movetment of each platform from its raised to its lowered position notwithstanding off-center loading of the platform. In addition, each platform is free to be rocked through a relatively large angle about the axis defined by the knife edge members 88 so as to divert an envelope thereon from the path of mail movement and into an associated one of several receiving cribs therebelow.

A yoke 90 is disposed in fixed relation on one side of each platform 86. Yokes 90 each include a downwardly depending leg 92 adapted to rotate the platform about the axis defined by knife edge members 88. This rotation is through a relatively large angle to tilt platforms 86 for disposal of an envelope resting thereon.

A stabilizing member 94 provided with a bifurcated upper end is mounted to move in parallelism with leg 92 by means of an extended stay 96 pivotally mounted through the lower ends of leg 92 and member 94. A balance beam 98 is supported upon a fulcrum 100 carried by a channel iron side frame member 102 and held in fixed relation thereto by a set screw 104. Fulcrum member 100 is formed with a pivot pin 106 extending through side frame member 102 and adapted to pivotally carry the bifurcated upper end portion of stabilizer member 94. Balance beam 98 is provided with an insert 108 received in a rectangularly shaped notch. Fulcrum 100 supports beam 98 for rocking weighing movement about the axis defined by the V-shaped insert 108.

A one end of beam 98 a counterweight tray 110 is mounted to carry a counterweight 112 removably resting on tray 110. A first fixed stop 114 in the form of an adjustable screw serves to limit upward travel of one end of beam 98 so as to define the uppermost position of the platform 86. A second fixed stop 116 serves to limit upward travel of the other end of beam 98 to define the lowermost position of the platform.

Another fixed stop 118 in the form of an adjustable screw, serves to limit rotational movement of stabilizer member 94 about a pivot point 120. A spring 122 fixed at one end to a frame portion and at its other end to the stabilizer member 94 serves to retain the stabilizer member in vertical orientation during weighing movement of leg 92. spring 122 permits rocking movement of stabilizer member 94 about pivot point 120 under longitudinal displacement of extended stay 96. Accordingly, spring 122 However, as will be further described below serves to provide resilient means urging the stabilizer member 94 firmly against fixed stop 118 to hold stabilizer member 94 upright during vertical weighing movements of said platform. Also, the spring 122 serves to yield under substantial forces acting to move extended stay 96 in a direction generally parallel with the beam 98.

Whenever leg 92 is carried to its lower position by a minimum weight on platform 86 a cyclically driven pawl 124 en ages and moves extended stay 96 longitudinally of beam 98. Extended stay 96 carries a tooth 126 extending therefrom adapted to move into the path of the cyclic moving pawl 124 whenever platform 86 and leg 92 are carried downwardly from their raised position. When leg 92 is in its raised position tooth 126 rides along the upper arcuate surface formed by the edge 128 of pawl 124. Subsequent downward movement of leg 92 during one cycle of operation is thereby precluded.

During operation of the apparatus there exists a possibility that an envelope may become jammed between one of the weighing platforms and either another weighing platform or the side frame of the apparatus. A linkage is provided whereby jammed envelopes are protected from damage.

A rotationally driven cam 130 serves to cyclically drive pawls 124 from platform leveling to platform tilting positions. A cam follower 132 is carried on one end of a bell crank 134. The other end 136 of bell crank 134 is formed with a drive pin 138 extending normal to the plane thereof. A connecting bar 140 is positively driven by bell crank 134 through a drive pin 138 (FIGURE 4). As bar 140 is positively driven in platform tilting direction, downwardly depending posts 142 pull pawl 124 along with the movement of bar 140 through a spring 144 forming a resilient coupling therebetween. Pawl 124 is mounted upon a lever arm pivoted at its upper end and carrying a stud 146 extending normal to the plane of bar 146. Bar 140 further carries adjustable stud contactors 148 for a purpose described further below. Positive driving movement of bar 140 is resisted by a spring 150 (FIGURE 4) extending between a frame portion and the end of bell crank arm 134. Accordingly, a return bias is imparted to bar 146 by spring 150. Thus bar 141 is coupled to each pawl 124 to drive it in a platform tilting direction.

A second connecting bar 152 is movable in parallelism with bar 140. A spring 154 (FIGURE 4) forms a driving connection between bar 140 and bar 152 to permit bar 152 to be restrained from moving in the event of a jammed condition.

As will be further described in detail below, an electrical switch is carried to move with one of the bars and a contactor is carried to move with the other. Normally, the switch and contactor are disposed to maintain the switch in one condition during movement of the bars in parallelism. Upon restraining one of the bars, namely bar 152 to provide a relative movement between the two bars, the electrical switch operates to terminate operation of the apparatus.

A plurality of parallel disposed pivotally mounted jam sensing levers 156 are pivoted from a frame portion about pins 158 and are pivotally coupled to bar 152 by pins 160. Accordingly, if pivotal movement is arrested for any one of the levers 156 about its associated pin 158, movement of the bar 152 will also be arrested. Spring 154, however, will permit bar 140 to continue moving while bar 152 remains restrained.

The lever 156 disposed in the region of hell crank 134 at the driving end of bar 152 is designated 156a. Lever 156a carries a suitable micro-switch 162 which is provided with an armature member 164. The armature member 164 is adapted to ride in contact with a contactor 166 which may be an adjustable screw carried on the arm 136 of hell crank 134. Thus when bar 152 is restrained and bar 140 continues to move, contactor 166 is separated from armature member 164 thereby operating switch 162 to a de-energizing condition thereof.

Operation of the foregoing jam sensing linkage proceeds as follows: Upon receipt of an envelope of a Weight associated with a particular platform 86, leg 92 is moved downwardly to position tooth 126 into the path of cyclic pawl 124. Bell crank 134 moves bar 140 forward to a platform tilting position (shown in dashed lines in FIG- URE 7) carrying all pawls 124 with it by means of springs 144. Assuming one of the platforms 86 to have become jammed at this time, the particular pawl 124 associated therewith will be restrained and an associated one of levers 156 will engage stud 146 of the particular pawl 124. Engagement between lever 156 and stud 146 serves to arrest further movement of bar 152 thereby providing a substantial relative movement between bar 140 and bar 152. This substantial relative movement is sensed by switch 162 so as to shut down operation of the equipment, it being understood that switch 162 is electri cally connected to operate motor 19 though this connection is not shown.

Assuming no jam to have occurred, all of pawls 124 will continue to move to their platform tilting position and, if the weight on the individual platforms is sulficient, carry extended stays 96 longitudinally of the apparatus thereby rocking yokes about the axis defined by knife edge members 88.

Return movement of bar 140, under urging of spring 156, pulls stud contactors 148 into engagement with each of studs 146 thereby moving pawls 124 to platform leveling position. Accordingly, as pawls 124 move to platform leveling position the lower ends of legs 92 (that is those that have been moved to tilting position) are returned so as to dispose yokes 96 and their associated platforms to level envelope receiving orientation. At this point it should be noted that cam 13% is arranged whereby a dwell occurs to retain bar with teeth 126 engaged by pawls 124 thereby precluding downward movement of platform 86 if, during the preceding movement of pawl 128 the platform was tipped. Accordingly, the first subsequent movement of bar 140 will serve to unlock platforms 86.

If, on the other hand, the weight of an envelope on the platform 86 is less than sufficient to lower the yoke 90 and tooth 126 into engaging position with the cyclic pawl 94, movement of the bar 140 to the left as shown in the figures will cause the pawl edge 128 to underride the tooth 126 to lock the yoke in position. On return movement of the bar 140 to the right, the same dwell mentioned above serves to retain the pawl slightly under the tooth 126 to likewise preclude downward movement of the platform 86. Thus, whether the platform is tipped or not during the preceding cycle, the scale is locked for a slight time period after the conveyor means ceases operation.

From the foregoing it will be evident that a high speed operation of mail sorting can be obtained by virtue of an extremely short downward movement of the weighing platforms which can, for example, be on the order of fif teen thousandths of an inch depending upon the thickness of the tooth formed at the end of the extended stay 96. Lightweight construction of the weighing mechanism is permitted by the balance beam arrangement and serves to minimize inertia when returning each platform to envelope receiving condition.

It will also be evident that an improved envelope separating technique is employed whereby presorting of envelopes to general classifications is unnecessary and wherein the need for adjustment of the envelope feeding station between runs has been eliminated. It will also be apparent that the weighing platform serves to define the path of envelope movement as well as being arranged to divert envelopes from their path. Thus, each platform performs weighing, path defining and sorting functions.

As mentioned, the cycle of operation of the above described apparatus is quite short and can be on the order of one second. In addition, to the above factors which contribute to the high speed operation of the equipment, it will also be observed that the apparatus is arranged whereby time sharing is advantageously accomplished. For example, as is shown in the timing and acceleration curves presented in FIGURE 9 it will be seen that the envelope-advancing projections remain stationary during the time represented between point XA and point XB from point XB to point XC, however, the Geneva mechanism serves to move the envelopes from one position to the next along the envelope path defined by the weighing platforms. Thus mail moves from the feeding mechanism to the first scale platform as well as from one platform to the next during this latter portion of each cycle. During the time that the envelope advancing mechanism is at rest, the weighing and sorting mechanism performs between points YA and YB as follows. Initially each scale is in its locked position. During the midportion of this time-span each scale is free to move and weigh an envelope at rest upon the platform. Accordingly, the platform either remains at its raised position or moves downwardly slightly to indicate an overbalancing envelope weight. At the end of this time-span, as shown by the dashed line commencing therein, the platforms begin to tilt if the weight has been sufiicient to move the platform to its lowered position. The platform becomes fully tilted just prior to the end of this time period and stays tilted until substantially the midpoint of the time span defined between ordinates B and C at which time the platform commences to return to its level position.

In the feeding mechanism, envelopes are advanced to the envelope engaging projections by virtue of the feeding arrangement during the latter portion of the time span indicated between ordinates A and B and this movement is terminated substantially at point ZB.

From the foregoing diagram, it will be readily apparent that the envelope engaging projections commence pushing an envelope forward along its path of movement prior to the time that the tilted platforms have been returned to their level position. However, even the widest envelope will have to be pushed at least half its width before it can fall off the preceding platform and where the envelope is of maximum width its leading edge will make contact with the subsequent platform substantially at the midpoint thereof whereby the leading edge of the envelope will be directed upwardly rather than having a tendency to fall into a crib. For ordinary envelopes of narrower width, the subsequent platform will have returned a considerable distance towards its substantially level condition prior to the time that the envelope being advanced is falling off the platform from which it is being pushed.

I claim:

1. A mail sorting apparatus comprising means defining a mail depository zone adapted to receive a quantity of envelopes of differing randomly occurring thicknesses and weights, a series of bi-stable weighing platforms defining a path of mail movement and adapted to receive said envelopes, each of said platforms being arranged for vertical Weighing movement from a raised to a lowered position upon receiving thereon an envelope of a predetermined minimum weight, intermittently moving conveyor means disposed adjacent said series of platforms for moving envelopes therealong, feeding means for separating and feeding each of said envelopes individually from said depository zone to said series of platforms and said conveyor means, a plurality of oribs, each of said cribs being disposed below a different one of said weighing platforms for receiving envelopes from the platforms, sensing and diverting means associated with each of said platforms for sensing platform movement to the lowered position thereof and for tipping the lowered platform downwardly and rearwardly about an axis extending transversely of the path to divert the envelope on the lowered platform to its associated crib.

2. Mail sorting apparatus as defined in claim 1 wherein each of said platforms is supported on a knife edge defining an axis laterally thereof, means serving to releasably stabilize said platforms to confine the plane thereof substantially to the horizontal during their movement from said raised to said lowered positions notwithstanding oifcenter loading of said platforms, said sensing and diverting means serving to overcome said means for releasably stabilizing the platform and to rock the platform through a large angle about said knife edge axis whereby an envelope thereon is diverted from said path to the crib associated with the rocked platform.

3. A mail sorting apparatus comprising means defining a mail depository zone adapted to receive a quantity of envelopes of differing randomly occurring thicknesses and weights, a series of bi-stable weighing platforms defining a path of mail movement and adapted to receive said envelopes, each of said platforms being arranged for vertical weighing movement from a raised to a lowered position upon receiving thereon an envelope of a predetermined minimum weight, each of said platforms being supported on a knife edge defining an axis laterally thereof, intermittently moving conveyor means disposed adjacent said series of platforms for moving envelopes therealong, feeding means for feeding each of said envelopes individually from said depository zone to said series of platforms and said conveyor means, a plurality of cribs, each of said cribs being disposed below a different one of said Weighing platforms for receiving envelopes from the platforms, sensing and diverting means associated with each of said platforms for sensing movement thereof to its lowered position and for diverting the envelope on the lowered platform to its associated crib, the last named means including a series of scale beams, the knife edge of each of said weighing platforms being supported at one end of each of said scale beams, a frame member, a series of fulcrums rigidly supported on said frame member, each of said fulcrums receiving one of said scale beams for rocking weighing movement thereon, first fixed stop means associated with each of said scale beams to limit upward travel of said one end thereof to define the raised position of said weighing platforms second fixed stop means associated with each of said scale beams to limit upward travel of said other end thereof to define the lowered position of said weighing platforms, a vertically depending leg rigidly connected at one end to each of said platforms, a first pivot point at the other end of each of said legs, a stabilizer member associated with and extending parallel to each of said legs, one end of said stabilizer members being pivotable at a point in the horizontal plane of said first pivot point, a second pivot point at the other end of each of said stabilizer members, an extended stay pivotally supported and extending between said first and second pivot points in substantially parallel relation to said beam, a third fixed stop, resilient means urging said stabilizer member firmly against said third fixed stop to hold said stabilizer member upright during vertical weighing movements of said platform and yielding under substantial forces acting to move said extended stay in a direction generally parallel with said beam, and cyclically driven pawl means adapted to engage and move said extended stay whenever said leg is carried to said lowered position.

4. Mail sorting apparatus as defined in claim 3 wherein said extended stay carries a tooth extending therefrom adapted to move with said downward movement of said leg into the path of said cyclic moving pawl means said tooth being disposed to ride upon the upper edge of said pawl means when said platform is in its raised position to thereby preclude downward movement of said leg and said platform.

5. Mail sorting apparatus as defined in claim 3 includ ing driving means for said cyclic moving pawl comprising a linkage whereby jammed envelopes are protected from damage, said linkage comprising a cam driven crank arm and resiliently coupled to each pawl to resiliently drive same in a platform tilting direction whereby any one of said pawls will cease movement in the event of a jam at its associated platform, a first spring urging said first connecting bar in a reverse direction, a second connecting bar movable in parallelism with said first bar, a second spring forming a driving connection between said first and second bars to permit said second bar to be restrained from moving in the event of a jammed condition, a plurality of parallel disposed jam sensing members pivotable with respect to the frame member and driven by said second connecting bar to follow a related one of said pawls, whereby upon cessation of movement by any one of said pawls in response to a jam at its associated platform, said second connecting bar will likewise cease movement, an electrical switch carried by one of said bars, a contactor being disposed to maintain said switch normally in one condition during movement in parallelism of said bars and to sense relative movement between said bars of a predetermined degree to alter the condition of said switch for terminating operation of said apparatus upon restraint of said second bar.

6. Mail sorting apparatus including a plurality of aligned platforms each disposed for vertical weighing movement, said platforms defining a path of envelope movement from one to the next, each said platform being supported on a knife edge serving to define an axis laterally thereof, means serving to releasab'ly stabilize said platforms to confine the plane thereof substantially to the horizontal during weighing movement from a raised to lowered position notwithstanding off-center loading of said platform, means serving to sense movement of the platforms to their lowered positions and to divert envelopes on the lowered platforms from said path, the last named means acting to overcome the first named means to elfect release thereof and rock each of the lowered platforms through a relatively large angle about their respective knife edges to tilt the platform downwardly and rearwardly whereby envelopes on the lowered platforms are diverted rearwardly from the path of accumulation therefrom.

7. Mail sorting apparatus including a plurality of aligned platforms each disposed for vertical weighing movement, said platforms defining a path of envelope movement from one to the next, each said platform being supported on a knife edge serving to define an axis laterally thereof, means serving to releasably stabilize said platforms to confine the plane thereof substantially to the horizontal during weighing movement from a raised to lowered position notwithstanding off-center loading of said platform, means serving to sense movement of the platforms to their lowered positions and to divert envelopes on the lowered platforms from said path, the last named means acting to overcome the first named means to effect release thereof and rock each of the lowered platforms through a relatively large angle about their respective knife edges whereby envelopes on the lowered platforms are diverted for accumulation therefrom, a series of scale beams, the knife edge of each of said weighing platforms being supported at one end of each of said scale beams, a counterweight carried at the other end of each of said scale beams, a frame member, a series of fulcrums rigidly supported on said frame member, each of said fulcrums receiving one of said scale beams for rocking weighing movement thereon, first fixed stop means associated with each of said scale beams to limit upward travel of said one end thereof to define the raised position of said weighing platforms, second fixed stop means associated with each of said scale beams to limit upward travel of said other end thereof to define the lowered position of said weighing platforms, a vertically depending leg rigidly connected at one end to each of said platforms, a first pivot point at the other end of each of said legs, a stabilizer member associated with and extending parallel to each of said legs, one

end of said stabilizer members being pivotable at a point in the horizontal plane of said first pivot point, a second pivot point at the other end of each of said stabilizer members, an extended stay pivotally supported and extending between said first and second pivot points in substantially parallel relation to said beam, a third fixed stop, resilient means urging said stabilizer member firmly against said third fixed stop to hold said stabilizer member upright during vertical weighing movements of said platform and yielding under substantial forces acting to move said extended stay in a direction generally parallel with said beam, and cyclically driven pawl means adapted to engage and move said extended stay whenever said leg is carried to said lowered position.

8. Mail sorting apparatus as defined in claim 7 wherein said extended stay carries a tooth extending therefrom adapted to move with said downward movement of said leg into the path of said cyclic moving pawl means, said tooth being disposed to ride upon the upper edge of said pawl to thereby preclude downward movement of said leg and said platform.

9. Mail sorting apparatus as defined in claim 8 including driving means for said cyclic moving pawl means comprising a linkage whereby jammed envelopes are protected from damage, said linkage comprising a cam driven crank arm, a first connecting bar positively driven by the crank arm and resiliently coupled to each pawl to resiliently drive same in a platform tilting direction whereby any one of said pawls will cease movement in the event of a jam at its associated platform, a first spring urging said first connecting bar movable in parallelism with said first bar, a second spring forming a driving connection between said first and second bars to permit said second bar to be restrained from moving in the event of a jammed condition, a plurality of parallel disposed jam sensing members pivotable with respect to the frame member and driven by said second connecting bar to follow a related one of said pawls, whereby upon cessation of movement by any one of said pawls in response to a jam at its associated platform, said second connecting bar will likewise cease movement, an electrical switch carrier by one of said bars, a contractor being disposed to maintain said switch normally in one condition during movement in parallelism of said bars and to sense relative movement between said bars of a predetermined degree to alter the condition of said switch for terminating operation of said apparatus upon restraint of said second bar.

10. Mail handling apparatus including means defining a mail receiving zone for the deposit of an accumulation of envelopes of varying and randomly occurring thicknesses, and envelope feeding means including a feeder wheel disposed to be rotated continuously in envelope delivering direction to move envelopes in a predetermined path, said feeder wheel carrying a first friction means extending around a limited arcuate extent of said wheel to provide intermittent frictional contact with said envelopes under continuous rotation of said wheel, a second friction means serving to apply a frictional drag to the top surface of envelopes passing therebeneath and developing a coefficient of friction with respect to said envelopes greater than envelope-to-envelope engagement and less than the coeflicient of friction between said first friction means and said envelopes, said second friction means being movable between raised and lowered positions and disposed for vertical pressuring movement downwardly onto said envelopes from above to apply said drag, means for provid ing said vertical pressuring movement including lifting means serving to positively raise said second friction means above said first friction means to a point higher than the thickness of envelopes to be passed therebetween, said lifting means being operative as an envelope is passed be tween said first and second friction means whereby said second friction means becomes operative only after the leading edge of the envelope has passed therebelow.

11. Mail handling apparatus according to claim 10 wherein said second friction means includes a first and second frictional surface, the first surface having a relatively high coefficient of friction and the second surface having a substantially lower coeflicient of friction and means for presenting only said low friction surface to an envelope below said second friction means when the downward pressuring movement of the second friction means is arrested by an envelope thereunder having a preselected thickness and is thereby maintained above said first friction means by a preselected distance, whereby upon passage of relatively thick envelopes holding the second friction means beyond said preselected distance, only said low friction surface contacts the upper surface of the envelope.

References Cited by the Examiner UNITED STATES PATENTS Depew 19870 Hothersall 209121 Payne 271--37 X Pekar 209121 Hayter 20912l Root 209-121 Gross 209121 Rabinow 27157 X M. HENSON WOOD, JR., Primary Examiner.

ROBERT B. REEVES, Examiner. 

1. A MAIL SORTING APPARATUS COMPRISING MEANS DEFINING A MAIL DEPOSITORY ZONE ADAPTED TO RECEIVE A QUANTITY OF ENVELOPES OF DIFFERING RANDOMLY OCCURRING THICKNESS AND WEIGHTS, A SERIES OF BI-STABLE WEIGHING PLATFORMS DEFINING A PATH OF MAIL MOVEMENT AND ADAPTED TO RECEIVE SAID ENVELOPES, EACH OF SAID PLATFORMS BEING ARRANGED FOR VERTICAL WEIGHING MOVEMENT FROM A RAISED TO A LOWERED POSITION UPON RECEIVING THEREON AN ENVELOPE OF A PREDETERMINED MINIMUM WEIGHT, INTERMITTENTLY MOVING CONVEYOR MEANS DISPOSED ADJACENT SAID SERIES OF PLATFORMS FOR MOVING ENVELOPES THEREALONG, FEEDING MEANS FOR SEPARATING AND FEEDING EACH OF SAID ENVELOPES INDIVIDUALLY FROM SAID DEPOSITORY ZONE TO SAID SERIES OF PLATFORMS AND SAID CONVEYOR MEANS, A PLURALITY OF CRIBS, EACH OF SAID CRIBS BEING DISPOSED BELOW A DIFFERENT ONE OF SAID WEIGHING PLATFORMS FOR RECEIVING ENVELOPES FROM THE PLATFORMS, SENSING AND DIVERTING MEANS ASSOCIATED WITH EACH OF SAID PLATFORMS FOR SENSING PLATFORM MOVEMENT TO THE LOWERED POSITION THEREOF AND FOR TIPPING THE LOWERED PLATFORM DOWNWARDLY AND REARWARDLY ABOUT AN AXIS EXTENDING TRANSVERSELY OF THE PATH TO DIVERT THE ENVELOPE ON THE LOWERED PLATFORM TO ITS ASSOCIATED CRIB. 